/* 布局相关 */
.flex {
  display: flex;
  align-items: center;
}
.flex-col {
  flex-flow: column;
}
.flex-wrap {
  flex-wrap: wrap;
}
.flex-1 {
  flex: 1;
}
.flex-none {
  flex: none;
}
.align-stretch {
  align-items: stretch;
}
.align-start {
  align-self: flex-start;
}
.justify-ct {
  justify-content: center;
}
.justify-sa {
  justify-content: space-around;
}
.justify-sb {
  justify-content: space-between;
}